721421447 has 2 divisors, whose sum is σ = 721421448. Its totient is φ = 721421446.

The previous prime is 721421423. The next prime is 721421461. The reversal of 721421447 is 744124127.

It is a strong prime.

It is an emirp because it is prime and its reverse (744124127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721421447 - 2⁶ = 721421383 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721421417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360710723 + 360710724.

It is an arithmetic number, because the mean of its divisors is an integer number (360710724).

Almost surely, 2^721421447 is an apocalyptic number.

721421447 is a deficient number, since it is larger than the sum of its proper divisors (1).

721421447 is an equidigital number, since it uses as much as digits as its factorization.

721421447 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12544, while the sum is 32.

The square root of 721421447 is about 26859.2897709526. The cubic root of 721421447 is about 896.8703837485.

The spelling of 721421447 in words is "seven hundred twenty-one million, four hundred twenty-one thousand, four hundred forty-seven".